Il6 MINERAL OGICAL QUERIES, 



of sienite ; but I have never seen any specimens, 

 or received any accurate account, of the rocks 

 that form its base, and the neighbouring coun- 

 try. Are we then to consider this great moun- 

 tain as a portion of the overlying, consequently 

 newest primitive formations, and that the upper 

 part is the second porphyry formation, and the 

 lower probably sienite, or newer granite, or 

 both? 



15. Does the porphyry at the fall of the Brauer, 

 near Blair, in Athol belong to the first or 

 to the second porphyry formation ? 



16. What are the geognostic characters and 

 relations of the metalliferous veins of Tyn» 



drum ? 



17. Is the granite rock of Loch Clony, in In- 

 verness-shire, old granite, sienite, or newest 

 granite ? 



18. Does the pitchstone of Ardnamurchan, in 

 Inverness-shire, belong to the newest floetz- 

 trap formation ? 



19. Does porphyry occur in beds in the transi- 

 tion mountains of Scotland ? 



Several appearances in the upper part of Dum- 

 friesshire and Lanarkshire, seem to intimate 

 that a porphyry, or a remarkably porphyritic 



